Projected impact of future climate conditions on the agronomic and environmental performance of Canadian dairy farms

Climate change is expected to increase agricultural productivity in Canada and in other northern countries but this increase will likely affect the environmental performance of dairy farms, one of the most important agricultural sectors in Canada. The objective of this study was to project the impact of climate change on the agronomic and environmental performance of a virtual dairy farm in each of three climatically contrasting areas of Canada through near future (2020-2049) and distant future (2050-2079) periods, using the Integrated Farm System Model (IFSM) and three climate models (CanESM2, CanRCM4, and HadGEM2). Under future climate conditions and relative to a reference period (1971-2000), projected yields of perennial forages and warm season crops increased, whereas those of small-grain cereals decreased slightly. Projected ammonia emissions increased on virtual farms of the three areas and in all future scenarios (+ 18% to + 54%). Methane emissions from manure storage increased (+ 26% to + 120%), whereas those from enteric fermentation and field manure application decreased. Projected farm N2O emissions changed only slightly relative to the reference period. Fossil fuel CO2 emissions related to field operations increased slightly, due to a larger number of forage cuts per year in future scenarios, but CO2 emissions related to grain drying decreased substantially. Projected losses of P increased on virtual farms of the three areas. The projected reactive N footprint of dairy farms in future scenarios varied more (15% to + 46%) relative to the reference period than the C footprint (-5% to + 9%). Although greenhouse gas mitigation should be a priority for dairy farms under future climate conditions, it should not overshadow the need for strategies to reduce reactive N losses.